One-way valve for plugging the brake air line of a tractor trailer when working on the air brake system



FIG. 1 is a perspective view of the one-way valve for plugging the brake air line of a tractor trailer when working on the air brake system embodying the design of the present invention.

FIG. 2 is a front end elevational view thereof.

FIG. 3 is a rear end elevational view thereof.

FIG. 4 is a side elevational view thereof, the side opposite being a mirror image of the side shown in FIG. 4.

FIG. 5 is a top plan view thereof.

FIG. 6 is a bottom view thereof. 

The ornamental design for a one-way valve for plugging the brake air line of a tractor trailer when working on the air brake system, as shown and described. 